Netopia 430 s Reference Guide

Page of 276
IP Setup
4-5
NAT guidelines
Obser ve the following guidelines when using NAT.
Only one node per internal network can supply a specific 
ser vice. In our example, if there is more than one web ser ver 
on the 10.0.0.0 network, the Netopia ISDN Router would not be 
able to differentiate incoming web traffic destined for each web 
ser ver. Similarly, external users cannot ping internal nodes, 
although the Netopia ISDN Router can respond to ping 
requests.
As mentioned earlier, you can enable NAT on one connection profile, 
disable it on another, and use the two profiles simultaneously.  The 
profiles might have the following attributes:
A “normal” profile connects to your branch or main office.  Your 
company network administrator has assigned you a local IP 
address range that is consistent with the address space 
assigned to your company so that you seamlessly integrate 
when connected.  The remote IP address and mask for this 
profile define only the company’s address space, so that the 
only IP traffic you send over this connection is for hosts and 
ser vers within your company.
A NAT profile connects to the internet via an ISP.  Even though 
the ISP assigns you a dynamic address each time you connect, 
there will be no conflict of address spaces, since NAT makes 
the corporate address you use locally invisible to the ISP.  You 
enter the ISP’s remote IP address as your default IP gateway so 
that any IP traffic not intended for your corporate intranet will be 
directed to the ISP.
Associate your primar y Domain Name Ser ver with whichever 
profile is more accessable.  If you choose for neither profile to 
be “dial-on-demand”, you may associate a secondar y DNS with 
the other profile.